U.S. Pat. No. 5,758,900 shows a protection system for a driver of a competition vehicle. The protection system includes a safety belt system having first and second shoulder belt parts, each of which is provided with one shoulder air bag attached thereto. Because the air bags are attached to the safety belt system, the safety belt system must be adjusted in order to adjust the position of the air bags relative to the driver. Furthermore, the safety belt system is relatively complex, and difficult to adjust. Consequently, such a protection system is not desirable for use in passenger vehicles.
U.S. Pat. No. 5,851,055 shows a passenger restraint system including a belt having a lap section, which may or may not be inflatable, and an inflatable torso section. The torso section has a first inflatable portion that contacts a passenger, and a second inflatable portion mounted in an enclosure that prevents substantial inflation of the second portion. The lengths of the first and second inflatable portions can also be varied so as to accommodate passengers of different sizes.